The San Diego Electric Railway (SDERy) was a mass transit system in Southern California, United States, using 600 volt DC streetcars and (in later years) buses. The SDERy was established by sugar heir and land developer John D. Spreckels in 1892. The railroad's original network consisted of five routes: the Fifth Street and Logan Heights Lines, the First and "D" Streets Lines, the Depot Line, the Ferry Line, and the "K" Street Shuttle. The company would establish additional operating divisions as traffic demands led to the formation of new lines. The company also engaged in limited freight handling primarily as an interchange with Spreckels' San Diego and Arizona Railway (SD&A) from 1923 to 1929.